Our invention comprises a high excursion or long travel damper for use in a split torque transmission or a lockup torque converter for a transmission of the kind shown in U.S. Pat. No. 4,509,389, which is assigned to the assignee of this invention. Our invention also may be applied, however, to automotive transmission concepts other than in the transmission arrangement shown in the '389 patent.
We are aware of long travel dampers for use in automotive vehicle drivelines having multiple ratio gearing and internal combustion engines wherein transient torque fluctuations during torque delivery from the engine to the torque input elements of the gearing are absorbed. An example of this is shown in Fall et al patent 4,304,107. Another example is shown in Lamarche patent 4,139,995.
The damper shown in the '107 patent comprises a driving member that may be connected to an impeller housing of the kind shown in the '389 patent. A driven disc is adapted to be connected to the turbine shaft of the converter shown in the '389 patent. The driving member and the driven disc of the damper are resiliently connected by two series of compression springs, one series being disposed in parallel relationship with respect to the other. So-called floating spacers are located between the springs in each series. The springs act as a cushion for absorbing torque fluctuations. In addition to the cushion effect, the damper of the '107 patent uses friction discs and disc actuating washer springs. The friction disc and the associated washer springs establish a friction lag in the spring system established by the series related springs as torque is transmitted from the converter impeller housing to the driven disc or turbine shaft of the torque converter.
The damper of the '995 patent is similar in concept to the damper of the '107 patent except that the spacers between the individual springs of each series are replaced by equalizer plates that are rotatably mounted in floating fashion on the hub of the converter turbine. Another example of a damper having both a spring cushion effect and a friction lag effect is described in U.S. Pat. No. 4,555,009.